1. Field of the Invention
The present invention relates to a method of fabricating a semiconductor device. More particularly, the present invention relates to a method of fabricating a semiconductor device including a metal-insulator-metal capacitor.
2. Description of the Related Art
Capacitors may be classified according to their junction structure, and may include metal-oxide-silicon (MOS) capacitors, p-n junction capacitors, polysilicon-insulator-polysilicon (PIP) capacitors, metal-insulator-metal (MIM) capacitors, and others. Apart from the MIM capacitors, these capacitors may use monocrystalline silicon or polycrystalline silicon as an electrode material on at least one side of the capacitor dielectric. However, monocrystalline silicon and polycrystalline silicon may exhibit a relatively high resistance when used as capacitor electrodes. Further, a depletion region may be generated when a bias voltage is applied to monocrystalline silicon or polycrystalline silicon electrodes, which may make the voltage unstable such that capacitance values cannot be maintained constant.
Frequency dependence may be decreased by reducing the resistance of capacitor electrodes, as in the case of the metal electrodes used in MIM capacitors. MIM capacitors, which exhibit a relatively small capacitance dependence on voltage and temperature, may be used for various kinds of analog devices, mixed-mode signal application devices, system on chip (SoC) applications, etc. The MIM capacitor has been applied to, for example, an analog capacitor or filter applied to analog or mixed-mode signal applications for wire/wireless communication devices, an RF capacitor for high frequency circuits, a capacitor for an image sensor, an LCD driver IC (LDI), etc.
As the degree of integration of semiconductor devices has increased, the demand for MIM capacitors having a high capacitance has also increased. However, typical methods of fabricating advanced MIM capacitors may require multiple masks in order to pattern the electrodes, which complicates the manufacturing process and reduces manufacturing productivity.